Abstract

Frank Lloyd Wright famously called for buildings to be designed in such a way as to promote a harmonious relationship between their occupants and the environment. Some of his most famous early organic works are the Prairie Houses, open-planned residences that feature distinct visual connections between their living spaces and exterior views. In 1991, Hildebrand argued that such visual and spatial properties are ideal for evoking positive emotional responses. To support this proposition, Hildebrand drew on prospect-refuge theory, which suggests that semi-enclosed locations that frame an outlook meet an innate human desire for inhabiting places that offer enhanced survival opportunities. Moreover, Hildebrand identified several of Wright’s designs, led by the Heurtley house, which Hildebrand argued clearly demonstrate this concept. While this proposition has been widely referenced, there is little evidence that the spaces in Wright’s Prairie Houses are similar in the way they shape and control vision. Moreover, the challenge facing architects who wish to design spaces that feature heightened prospect-refuge relationships is that there is no clear and consistent way of measuring these properties. It is this challenge, of measuring the geometric properties of the space-view relationship, that is the focus of the present paper. Using the Heurtley house as an example, this paper examines the capacity of mathematical visibility analysis techniques to quantify prospect-refuge characteristics. Thus, this paper is not a test of prospect-refuge theory, but of the viability of mathematical techniques for use in such a test. Specifically, the paper uses isovists to model the visual experience of the living room in the Heurtley house before considering if the mathematical results are capable of usefully quantifying prospect-refuge characteristics.